I have a second gen Ultra X2 550w, and it has served up all the power I need, with the benefit of stability
Now you did it! You mentioned the one key word needed when deciding on makes and models to go iwth. "Stability"!
That also insures a little more system "stability" as well. When a system only draws a certain amount of amps like 10 for example a 450w with 20 and "stable" will see better results then some 1,000w loser that flakes out whenever a good load is placed on it. You'll never need 50-100amps total unless you are running a 12v air conditioner off the same supply. Anything over a certain amount is usually overkill.